1. Technical Field
The present invention relates to a facsimile machine having a telephone answering function which can selectively perform a recording operation and a facsimile operation, i.e., which can selectively record a voice message from a calling side and transmit image data between the calling side and the facsimile machine.
2. Background Art
A facsimile machine having a telephone answering function is known in the art. If such a facsimile machine is set to the answering mode and there is a call from outside, the facsimile machine sends a reception message to the calling side and starts the recording operation. During the recording operation, if the facsimile machine detects a facsimile signal such as a CNG signal sent from the calling side, the facsimile machine switches the connection from the telephone line to the facsimile line so that the facsimile communication is allowed to start. Conventionally, when the facsimile machine is brought into the facsimile operation after the initiation of the recording operation, the recorded voice is always erased.
As a result, if the calling side sends a voice message and a facsimile message in turn, the facsimile machine on the receiving side cannot hold the voice message and an operator on the receiving side cannot know what message is sent.
Regarding this disadvantage, another type of facsimile machine having a telephone answering function is proposed. Specifically, a facsimile machine which does not erase the voice message even if the facsimile operation is started after the initiation of the voice recording. However, this facsimile machine only records a CNG signal of 1,100 Hz or non-voice situation is recorded when the facsimile message is transmitted from the calling side without the voice message. This is uncomfortable to an operator on the receiving side when he plays the recorded information and wastes a memory capacity of the recording unit in the facsimile machine.
A conventional facsimile machine has another problem: If a handset (telephone receiver) or the facsimile machine on the calling side is on-hooked after the initiation of the recording operation on the receiving side, the recorded information is not erased but maintained regardless of presence of the voice message from the calling side. Therefore, if the calling side on-hooks the handset without the voice message, the facsimile machine on the receiving side may record "(no voice)" and a clanging noise. This is also uncomfortable to the operator on the receiving side and wastes the memory capacity of the recording unit of the facsimile machine on the receiving side.
In short, the conventional facsimile machines do not have means for determining whether a voice message is actually sent from the calling side.